A detailed analysis of the MDAH-TAMVEC neutron therapy trials for head and neck cancer.

The local control and survival rates with neutrons-only, mixed-beam, and conventional treatment were similar in the pilot studies, although the complication rate with mixed-beam irradiation was significantly less than that seen with the other treatment modalities. In the randomized trial, the local control and survival rates were better with mixed beam irradiation than with photons although the difference is not statistically significant. In this analysis, there were no tumor sites where any one treatment modality showed a marked superiority over another although neutron and mixed-beam therapy seemed to be most promising for faucial arch, base of tongue, pharyngeal wall, and salivary gland tumors. Analysis of the sites of failure indicated that neutron or mixed-beam therapy may be more effective than conventional radiotherapy in the management of regional lymph-node metastasis. In this study, dose-response relationships for local control and complications were demonstrated for the group treated with 50 MeVd leads to Be neutrons alone. The optimum dose was approximately 2100 radn gamma in 6 1/2 weeks, however, the range of acceptable neutron doses was narrow.